An ever increasing demand for stable compact local oscillator sources in military and commercial communication systems established a need for frequency multipliers. The frequency multiplier with a single nonlinear MESFET (metal-semiconductor field effect transistor) is an efficient, low power way of satisfying the demand. Typically, a conventional oscillator generates a submultiple signal which is input to the frequency multiplier, thereafter, the frequency multiplier outputs a desired multiple frequency or output frequency.
Currently, there are active frequency multipliers and passive frequency multipliers with input frequencies above 2 GHz. The passive frequency multipliers often use diode multiplication technology which has several disadvantages when compared to active frequency multipliers. Some of the disadvantages associated with diode multipliers includes temperature induced parasitic oscillation, high input power requirement and narrow bandwidth. Also, extensive filtering is required to suppress unwanted harmonics.
Active frequency multipliers have several advantages including low power operation, wide bandwidth, low distortion, small dimensions, and temperature stability. However, traditional "odd order" active multipliers require the use of an idler circuit to short the fundamental frequency. The idler circuit appears as a small inductance connected to the MESFET and ground. A problem with the idler circuit is that it limits the bandwidth of the frequency multiplier, thereby adversely affecting the performance of the frequency multiplier.
Accordingly there is a need for a "odd order" MESFET frequency multiplier that displays improved efficiency across a broadband with low AM-to-FM conversion noise and enhanced spurious suppression. There is also a requirement to minimize the use of an idler circuit without sacrificing performance. These and other needs are satisfied by the odd order MESFET frequency multiplier of the present invention.